Methods of making oligomers, coating compositions containing them, and coated articles

Abstract

An oligomer is made by capping a uretdione compound of structure with a compound (II) having an active hydrogen and a carbamate or cyclic carbonate group under conditions in which the isocyanate groups but not the uretdione group react. The product (III) is either reacted with a reactant having at least two active hydrogens under reaction conditions that cleave the uretdione ring, after which any cyclic carbonate groups may be converted to carbamate groups, or a product (III) having cyclic carbonate groups is reacted with ammonia or primary amine to provide uretdione with a hydroxy carbamate group that is then self-condensed under uretdione ring-opening conditions. A curable coating composition comprises the oligomer; a coated article is prepared by applying a layer of the curable coating composition and curing the applied layer.

What is claimed is: 
     
       1. A method of making an oligomer, comprising:
 (a) reacting one mole of a uretdione compound (I) 
 
       
         
           
           
               
               
           
         
       
       wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic;
 with two moles of compound (II) selected from compounds having one group having an active hydrogen reactive with isocyanate and further having a primary carbamate group or a cyclic carbonate group to form a compound (III), and 
 (b) reacting compound (III) with a reactant having at least two active hydrogen-containing groups selected from the group consisting of polyols, polyamines having at least two amine groups selected from primary and secondary amine groups, and aminoalcohols having at least one amine group that is a primary or secondary amine group under reaction conditions that cause the uretdione ring to cleave and react with the active hydrogens to form the oligomer. 
 
     
     
       2. A method according to  claim 1 , wherein the compound (II) has a structure (IIa) or a structure (IIb): 
       
         
           
           
               
               
           
         
         wherein X is O or NR 2 , wherein R 2  is H or alkyl having 1 to 6 carbon atoms; n is 1 to 4; and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms. 
       
     
     
       3. A method according to  claim 2 , wherein R includes one or more heteroatoms in a group selected from ether, ester, amide, tertiary amine, urea, and urethane groups. 
     
     
       4. A method according to  claim 1 , wherein compound (III) comprises a structure selected from the group consisting of structures (IIIa), (IIIb), and (IIIc): 
       
         
           
           
               
               
           
         
         wherein X is O or NR 2 , wherein R 2  is H or alkyl having 1 to 6 carbon atoms; n is 1 to 4, and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms. 
       
     
     
       5. A method according to  claim 4 , wherein R includes one or more heteroatoms that are in a group selected from ether, ester, amide, tertiary amine, urea, and urethane groups. 
     
     
       6. A method according to  claim 1 , wherein the oligomer comprises a cyclic carbonate group, further comprising a step of reacting the cyclic carbonate group with ammonia to provide a carbamate group. 
     
     
       7. A method according to  claim 1 , wherein the oligomer has a structure selected from the group consisting of 
       
         
           
           
               
               
           
         
         wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic; X is O or NR 2 , wherein R 2  is H or alkyl having 1 to 6 carbon atoms; n is 1 to 4, and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms, m is an integer that is 1 or greater when X is NH or 2 or greater when X is not NH, and P represents an m-valent core that is the residue of the reactant having at least two active hydrogen-containing groups. 
       
     
     
       8. A method according to  claim 7 , wherein the oligomer has the structure (IVb) and is further reacted with ammonia. 
     
     
       9. A method of making an oligomer, comprising:
 (a) reacting one mole of a uretdione compound (I) 
 
       
         
           
           
               
               
           
         
       
       wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic;
 with two moles of compound (II) selected from compounds having one group having an active hydrogen reactive with isocyanate and further having a cyclic carbonate group to form a compound comprising a structure 
 
       
         
           
           
               
               
           
         
       
       wherein n is 1 to 4 and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms, 
       that is then further reacted with ammonia to produce a compound comprising a structure (IIId): 
       
         
           
           
               
               
           
         
       
       wherein R and R 1  are as previously defined, and each R 3  independently has a structure 
       
         
           
           
               
               
           
         
       
       wherein n is as previously defined and
 (b) reacting the compound comprising the structure (IIId) with a reactant having at least two active hydrogen-containing groups selected from the group consisting of polyols, polyamines having at least two amine groups selected from primary and secondary amine groups, and aminoalcohols having at least one amine group that is a primary or secondary amine group under reaction conditions that cause the uretdione ring to cleave and react with the active hydrogens to form the oligomer. 
 
     
     
       10. A method according to  claim 9 , wherein the oligomer has a structure comprising repeating monomer units of structures selected from the group consisting of 
       
         
           
           
               
               
           
         
       
       and combinations thereof, wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic; and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms. 
     
     
       11. A method of making an oligomer, comprising:
 (a) reacting one mole of a uretdione compound (I) 
 
       
         
           
           
               
               
           
         
       
       wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic;
 with two moles of compound (II) selected from compounds having one group having an active hydrogen reactive with isocyanate and further having a cyclic carbonate group and compounds having one group having an active hydrogen reactive with isocyanate and further having a primary carbamate group to form a compound comprising a structure 
 
       
         
           
           
               
               
           
         
       
       wherein n is 1 to 4 and R is alkyl, aryl, alkylaryl, or arylalkyl having up to 12 carbon atoms and optionally including one or more heteroatoms, 
       that is further reacted with ammonia to produce a compound comprising a structure (IIIe): 
       
         
           
           
               
               
           
         
       
       wherein X is O or NR 2 , wherein R 2  is H or alkyl having 1 to 6 carbon atoms, R and R 1  are as previously defined, and each R 3  independently has a structure 
       
         
           
           
               
               
           
         
       
       wherein n is as previously defined and
 (b) reacting the compound comprising the structure (IIIe) with a reactant having at least two active hydrogen-containing groups selected from the group consisting of polyols, polyamines having at least two amine groups selected from primary and secondary amine groups, and aminoalcohols having at least one amine group that is a primary or secondary amine group under reaction conditions that cause the uretdione ring to cleave and react with the active hydrogens to form the oligomer. 
 
     
     
       12. A method according to  claim 11 , wherein the oligomer has a structure selected from the group consisting of 
       
         
           
           
               
               
           
         
         structures with repeating monomer units of structures: 
       
       
         
           
           
               
               
           
         
         and combinations thereof, wherein m is an integer that is 1 or greater when X is NH or 2 or greater when X is not NH, and P represents an m-valent core that is the residue of the reactant having at least two active hydrogen-containing groups. 
       
     
     
       13. A method of making an oligomer, comprising:
 (a) reacting one mole of a uretdione compound (I) 
 
       
         
           
           
               
               
           
         
       
       wherein each R 1  is independently selected from alkylene groups having 1 to 12 carbon atoms, arylene groups having 5 to 12 carbon atoms, and arylalkylene and alkylarylene groups having 6 to 15 carbon atoms, wherein alkylene groups, alkylene portions of arylakylene groups, and alkyl portions of alkylarylene groups are linear, branched, or cyclic;
 with two moles of compound (II) having one group having an active hydrogen reactive with isocyanate and further having a cyclic carbonate group to form a compound (III), 
 (b) reacting compound (III) with ammonia to produce a product having groups selected from the group consisting of 
 
       
         
           
           
               
               
           
         
       
       and combinations thereof, wherein n is 1 to 4;
 (c) self-condensing the product under uretdione ring-opening reaction condition to make the oligomer.